物化环境对化妆品液晶性的影响

Influence of physicochemical environment on liquid crystal status of cosmetic emulsion

以硬脂酸蔗糖酯和失水山梨醇硬脂酸酯的复配物 (SSE) /C16～ 18醇 /甘油为复合乳化剂制备液晶型化妆品乳液。考察了柠檬酸、pH值、离子强度和剪切速率对该乳液体系的稳定性和液晶性的影响。实验条件下 ,各体系对柠檬酸的敏感性比较强 ,但与pH值的关系不明显。加入柠檬酸对液晶数量和形状均有影响 ,柠檬酸的加入量大于 0 0 1%时乳液变稀 ,液晶减少。NaCl的离子强度效应主要是对乳液粒径及稳定性的影响 ,对液晶性影响不大。NaCl加入量≤ 0 3 %对乳状液及液晶的形成并无不良影响 ;NaCl加入量 >0 3 %乳液粒径明显变粗。乳状液粒子的粒径随剪切速率的减小而增大 ,粒径 <5 μm时液晶性较好。

Cosmetic emulsions containing liquid crystal were prepared by using the mixture of sucrose stearate and span as a primary emulsifier(SSE)while C 16～18 fatty alcohol and glycerol as co-emulsifiers.The effect of dosage of citric acid,pH,ion strength and shearing rate on the stability and liquid crystal status of the emulsion was investigated.It is showed that the emulsions are sensitive to citric acid but have no evident relationship with pH.Adding citric acid affects the amount and shape of liquid crystal status in the emulsion,and the amount of liquid crystal becames less and the emulsions became thinning while the dosage of citric acid was more than 0 01 % .The ion strength of NaCl doesnt alter the status of liquid crystal significantly but affects the particle diameter and stability of emulsions mainly.No disadvantage was found to emulsion stability and liquid crystal status if the dosage of NaCl was less than 0 3 % ,while the particle diameter of emulsion enlarged dramatically if the dosage of NaCl was more than 0 3 % .The particle diameter of emulsion enlarged while the shearing rate reduced.The status of liquid crystal were better if the particle diameter were less than 5 μm .